Detection of ocular disease and abnormalities in preschool children is important to prevent long-term vision impairment. During early development, the child's brain attempts to process visual information that is received in both of the child's eyes. However, if an ocular malady or impairment exists in one of the child's eyes which goes untreated for an extended period of time, the brain eventually stops processing information from the diseased eye, and leads to the severe ocular condition of amblyopia. Treatment of amblyopia is required at an early stage of child development before the condition becomes irreversible.
While early detection of ocular disease and abnormalities in preschool children is desirable, the ability of an ophthalmologist to identify certain eye maladies in young children is complicated by the age of the child, and in many cases, the inability of the child to communicate with the ophthalmologist. Common diseases and abnormalities which must be detected and treated in children include misalignment of the optical axes of the eyes (strabismus), refractive errors which cause nearsightedness (myopia) and farsightedness (hypermetropia), astigmatism, scarring of the cornea, and cataracts.
In the past, ocular screening of a patient's eyes has been achieved by flashing a beam of light at the patient's eyes, and recording retinal reflections from the patient's eyes on conventional 35 mm film or a charged coupled device (CCD). In this known procedure, the flash beam of light is positioned to travel off of, but nearly coincident with, an optical axis defined by the patient's eyes. The incoming flash beam of light is refracted by the lens of the patient's eye and falls generally on the pigmented macula and fovea of the patient's eye. A portion of the incoming light is reflected from the retina as a retinal reflection or retinal reflex which is then recorded by the camera for later evaluation by an ophthalmologist. Based on an evaluation of the retinal reflection, which may take days or even months to develop and review, the ophthalmologist is able to identify and correct certain ocular maladies.
In this ocular screening process, it is critical that the patient's eyes focus on the camera lens, and that the camera lens focus on the patient's eyes. Thus, alignment of the child's eye on the optical axis of the camera lens must be maintained throughout the screening procedure to insure that accurate retinal reflections are recorded. To focus the child's eye on the lens of the camera, known systems have used a series of lights, images, or an audible sound source positioned at or near the camera lens to attract the child's eyes to the camera lens. Other ocular systems have included a defocusing mechanism that presents an image having two focal lengths to defocus the eyes of the patient during the screening procedure.
Notwithstanding the advancements made in the prior art in the field of ocular screening devices for children, there is a need for an ocular disease and abnormality detection device which improves focusing of a patient's eyes on the lens of a camera during the screening procedure. There is also a need for an ocular disease and abnormality detection device which improves alignment verification of the patient's eyes before a retinal reflection is recorded. There is also a need for an ocular disease and abnormality detection device that rapidly processes and displays the recorded retinal reflections to provide faster evaluation of the information contained in the retinal reflection.